New members of a class of iron-thiolate-nitrosyl compounds: trinuclear iron-thiolate-nitrosyl complexes containing Fe(3)S(6) core

The neutral trinuclear iron-thiolate-nitrosyl, [(ON)Fe(mu-S,S-C(6)H(4))](3) (1), and its oxidation product, [(ON)Fe(mu-S,S-C(6)H(4))](3)[PF(6)] (2), were synthesized and characterized by IR, X-ray diffraction, X-ray absorption, electron paramagnetic resonance (EPR), and magnetic measurement. The five-coordinated, square pyramidal geometry around each iron atom in complex 1 remains intact when complex 1 is oxidized to yield complex 2. Magnetic measurements and EPR results show that there is only one unpaired electron in complex 1 (S(total) = 1/2) and no unpaired electron (S(total) = 0) in 2. The detailed geometric comparisons between complexes 1 and 2 provide understanding of the role that the unpaired electron plays in the chemical bonding of this trinuclear complex. Significant shortening of the Fe-Fe, Fe-N, and Fe-S distances around Fe(1) is observed when complex 1 is oxidized to 2. This result implicates that the removal of the unpaired electron does induce the strengthening of the Fe-Fe, Fe-N, and Fe-S bonds in the Fe(1) fragment. A significant shift of the nuNO stretching frequency from 1751 cm(-1) (1) to 1821, 1857 cm(-1) (2) (KBr) also indicates the strengthening of the N-O bonds in complex 2. The EPR, X-ray absorption, magnetic measurements, and molecular orbital calculations lead to the conclusion that the unpaired electron in complex 1 is mainly allocated in the Fe(1) fragment and is best described as {Fe(1)NO}7, so that the unpaired electron is delocalized between Fe and NO via d-pi* orbital interaction; some contributions from [Fe(2)NO] and [Fe(3)NO] as well as the thiolates associated with Fe (1) are also realized. According to MO calculations, the spin density of complex 1 is predominantly located at the Fe atoms with 0.60, -0.15, and 0.25 at Fe(1), Fe(2), and Fe(3), respectively.     

Haplotype assembly from aligned weighted SNP fragments

Given an assembled genome of a diploid organism the haplotype assembly problem can be formulated as retrieval of a pair of haplotypes from a set of aligned weighted SNP fragments. Known computational formulations (models) of this problem are minimum letter flips (MLF) and the weighted minimum letter flips (WMLF; Greenberg et al. (INFORMS J. Comput. 2004, 14, 211-213)). In this paper we show that the general WMLF model is NP-hard even for the gapless case. However the algorithmic solutions for selected variants of WMFL can exist and we propose a heuristic algorithm based on a dynamic clustering technique. We also introduce a new formulation of the haplotype assembly problem that we call COMPLETE WMLF (CWMLF). This model and algorithms for its implementation take into account a simultaneous presence of multiple kinds of data errors. Extensive computational experiments indicate that the algorithmic implementations of the CWMLF model achieve higher accuracy of haplotype reconstruction than the WMLF-based algorithms, which in turn appear to be more accurate than those based on MLF.     

Sol-gel Processing of a Transparent Upconversion Luminescent Film with β-Na YF_4:Yb~(3+), Er~(3+) Microrods as Activator

β-Na YF4:Yb3+,Er3+ microrods were synthesized through hydrothermal methods. Polyethylene glycol with molecular weight of 6000 was used as surfactant. A series of transparent silica gel films with upconversion luminescence property was prepared through sol-gel method; the prepared β-Na YF4:Yb3+,Er3+ microrods were used as activator. The silica gel films show strong upconversion emission under excitation of 980-nm laser beam.     

An Integrative Biosensor Based on Contra-Directional Coupling Two-dimensional Photonic Crystal Waveguides

We propose an integrative biochemical sensor utilizing the dip in the transmission spectrum of a normal singleline defect photonic crystal （PC） waveguide, which has a eontra-directional coupling with another PC waveguide. When the air holes in the PC slab are filled with a liquid analyte with different refractive indices, the dip has a wavelength shift. By detecting the output power variation at a certain fixed wavelength, a sensitivity of 1.2 × 10^-4 is feasible. This structure is easy for integration due to its plane waveguide structure and omissible pump source. In addition, high signal to noise ratio can be expected because signal transmits via a normal single-line defect PC waveguide instead of the PC hole area or analyte.     

无氧铜冲击熔化温度的辐射法测量

 在发生冲击熔化的情况下，金属样品/窗口界面压力下的熔化温度与卸载温度数值相等，且十分接近于界面温度值。根据这一结论，利用二级轻气炮加载手段和光辐射法测温技术，用氟化锂（LiF）单晶作透明窗口，获得了110~140 GPa压力范围内无氧铜的熔化温度。实验表明，无氧铜的高压熔化温度数据与文献发表的无氧铜高压声速实验结果是一致的，铜的高压熔化规律可用Lindemann熔化定律近似描述。采用的熔化温度测量方法不必反演出冲击温度，简化了冲击熔化温度的数据处理方法，为金属冲击熔化温度测量提供了一种潜在的技术途径。     

The Phase Transition of Eu2O3 under High Pressures

Pressure-induced phase transition of cubic Eu2 03 is studied by angle-dispersive x-ray diffraction （ADXD） up to 42.3 GPa at room temperature. A structural transformation from a cubic phase to a hexagonal phase is observed, which starts at 5.0 GPa and finishes at about 13.1 GPa. The phase transition leads to a volume collapse of 9.0% at 8.6 GPa. The hexagonal phase of Eu2 03 maintains stable up to the highest experiment pressure. After re/ease of pressure, the high-pressure phase transforms to a monoclinic phase. The pressure-volume data are fitted with the Birch-Murnaghan equation of state. The bulk moduli obtained upon compression from the fitting are 145（2） GPa and 151（6） OPa for the cubic and hexagonal phases, respectively, when their first pressure derivatives are fixed at 4.     

白簕多糖的提取工艺和含量比较

经多糖确证性实验首次证明白簕中含有多糖成分,不同部位的多糖含量不同,白簕中茎皮的多糖含量最高。单因素实验法对影响多糖得率的主要因素进行了分析,正交实验优化了多糖提取的工艺条件,研究表明：白簕茎皮中提取多糖类成分的最佳条件为：辐射时间60s、料液比1∶20、醇沉浓度70%、提取次数3次。在最佳条件下总多糖的含量为6.28mg/g。     

煤油热沉与热裂解反应特性的试验研究

本文设计了一种煤油热裂解反应特性与热沉测量试验系统,利用该试验系统和原始标定法的热损测量方法,测量出了在亚临界和超临界压力下煤油热裂解反应的热沉大小,并进行了热裂解反应主要分解产物成分含量的测定与分析。结果表明：壁温随热流密度增加而增加;在相同燃油温度条件下,压力增大,热沉降低;裂解反应气体的浓度变化主要受到燃油温度和...     

氢化物原子荧光光度法测定水中硒方法的改进

考察适于本地区水中硒含量测定的方法。参考国家标准的生活饮用水检验方法(GB/T5750—2006),对本地区的水质进行了多次的检测。不加入掩蔽剂有良好的线性关系,r=0.9996,RSD=1.87%,DL=0.28μg/L,回收率为97.5%—103.8%。硒的含量在0—50μg/L之间。该方法简捷,易于掌握,灵敏度高,稳定,准确。     

Interface of quasicrystal and crystal

A model on the coexisting phase of quasicrystal-crystal is proposed,with which we concretely investigate the interface effects for coexisting phases of one-dimensional orthorhombic quasicrystal-isotropic crystal and three-dimensional icosahedral quasicrystal-cubic crystal.The phason strain fields which play an important role in some processes are determined.Some factors affecting the strain fields,e.g.,the material constants of phonon,phason,phonon-phason coupling of the quasicrystal and the elastic modulus and the size of the crystal are also explored.